Variable speed transmission



y 1965 T. N. TYLER 3,183,729

VARIABLE SPEED TRANSMISSION Filed Jan. 12, 1962 5 Sheets-Sheet 1 FIG INVENTOR. TOMMY N. TYLER ATTO R N E Y.

May 18, 1965 'r. N. TYLER VARIABLE SPEED TRANSMISSION Filed Jan. 12, 1962 l 5 Sheets-Sheet a INVENTOR. TOMMY N. TYLER ATTORNEY.

May 18, 1965 'r. N. TYLER 3,183,729

VARIABLE SPEED TRANSMISSION Filed Jan. 12, 1962 5 Sheets-Sheet 3 FIG. 3

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ATTORNEY.

United States Patent 3,183,729 VARIABLE SPEED TRANSMISSION Tommy N. Tyler, Littleton, Colo., assignor to Honeywell, Inc., a corporation of Delaware Filed Jan. 12, 1962, Ser. No. 165,764 Claims. (Cl. 74-1905) This invention relates to a self-adjusting, variable-speed, mechanical transmission utilizing friction. This transmission automatically adjusts the speed and torque with which the output element is driven so as to compensate for any changes in load applied to the output element.

One use to which the transmission of this invention has been put is in oscillographic recorders such as those shown in United States Patent 2,580,427; C. A. Heiland; patented January 1, 1952. Such recorders include means, for example, an electric motor, for driving a long sheet of paper, or the like, which is sensitive to radiations that fall upon the sheet and form a record thereon. Such record sheets are driven at a uniform speed and are wound upon a take-up roller. Obviously, the diameter of the roll of paper on the take-up roller increases as the paper is wound up on the take-up roller. This increase in diameter of the roll of paper has two bad effects. The tension which the roll of paper on the take-up roller exerts on the driving means is increased. If the speed of the driving means is increased, paper is fed to the take-up roller faster than it can be accommodated thereon so that the length of paper between the driving means and that take-up roller increases providing slack in the paper between the take-up roller and the driving means.

It is an object of this invention to avoid these bad effects by the provision of the transmission of this invention. This transmission maintains the tension which the roll of paper on the take-up roller exerts on the driving means constant. This transmission also provides an increase in speed of rotation of the take-up roller when the driving means accelerates so that there is no slack in the paper being fed to the take-up roller.

More specifically, it is an object of this invention to provide a mechanical transmission comprising, an input disc, an output disc parallel to the input disc, and an intermediate wheel mounted on an axis substantially parallel to the faces of said discs so that the plane of the intermediate wheel is at right angles to said axis. This intermediate wheel is movable lengthwise and in rotation about the axis so as to transmit the motion of the input disc to the output disc. The axis on which the intermediate wheel is mounted is pivoted so that the path of axial movement of the intermediate wheel may move from one side of a plane connecting the axes of the discs to the other side of said plane. Because of this pivot, when the axis on which the intermediate wheel is mounted moves from one side of the plane connecting the axes of the discs to the other side of the plane, the plane of the intermediate wheel is at an angle to the plane connecting the axes of the pivotation of the discs. Therefore, the input disc applies a component of force to the intermediate wheel and causes the intermediate wheel to move along the axis on which the intermediate wheel is mounted and thereby to vary the respective distances between the intermediate wheel and the axes of pivotation of said discs. This varies the speed and torque with which the output disc is driven.

It is a further object of this invention to provide a transmission driving a spindle or take-up roller on which a roll of paper is mounted which decreases the speed at which the take-up roller is driven as the diameter of the roll of paper on the take-up roller increases and also increases the torque at which the spindle is driven so that the tension exerted by the roll of paper on the take-up roller at its periphery is substantially constant.

A better understanding of the present invention may be had from the following detailed description when read in connection with the accompanying drawings, in which:

FIG. 1 is a top or plan view.

FIG. 2 is a vertical section on line 22 of FIG. 1 as viewed in the direction of the arrows.

FIG. 3 is an end view with parts broken away.

FIG. 4 is a simplified diagram viewed from the same direction as FIG. 3 and useful in explaining the invention.

The recorder of this invention includes a stationary frame 1 in which the various moving parts of first and second transmission devices are mounted. The first transmission device la carries on it an output element such as a pulley P which drives the recording medium or spool of an oscillographic recorder. Output shaft 2 of the transmission 1b is mounted in frame 1 by suitable bearings and carries, at its right end, output disc 3 which has on its working face a disc facing 4 of a material similar to cork. The output shaft 2 drives the take-up spool of the recorder.

The input disc 6 is mounted on input shaft 8 which is the input to transmission 112 from another output of transmission In, and is suitably mounted in bearings in frame 1. Input disc 6 carries a disc facing 7 and has a portion of its face parallel to and overlapping with a portion of the face of output disc 3.

Between the output disc 3 and the input disc 6 is mounted an intermediate wheel, generally indicated 15. Portions of the rim of intermediate wheel 15 engage with the working face of the output disc 3 and with the working face of the input disc 6. Wheel 15 thereby transmit s motion from one disc to the other disc.

The axis of input shaft 8 forms the pivot about which intermediate wheel 15 rocks. On shaft 8 is mounted a bell crank lever, generally indicated 9, and having arms 21 and 22. Arm 21 has attached to one end of it a perforated support which carries one end of an intermediate shaft 14, the other end of which is mounted in lever 9'. Intermediate wheel 15 is movable axially and in rotation about shaft 14. Intermediate wheel 15 comprises a ring 16 of rubber or light asphalt material. Portions of ring 16 contact the surfaces of discs 3 and 6. A generally flat, leaf spring 10 is secured by means of a plate 11 to lever 9. The right hand end of spring 10 is forked so that it passes under the head of a screw 12 mounted on a stationary portion of frame 1. A coil spring 13 bears, at its lower end, against a nut 23 and, at its upper end, against the under side of spring 10. Lever 9 is biased for counter-lockwise movement around shaft 8 by spring 10.

Arm 22 of lever 9 carries at its end a screw 20 which may engage, at its lower end, with a piston rod 28 mounted in a cylinder 27 carried by frame 1. Piston rod 28 and cylinder 27 form parts of a damping device. Spring 13 is a means for holding the end of spring 10 under the head of screw 12. This provides for lateral motion of spring 10 during bending.

Intermediate wheel 15 is clamped between output disc 3 and input disc 6 by means of a'flat spring 17 which abuts, at its center, against a thrust bearing 18 on shaft 2, and at its opposite ends, adjustably against frame 1, by means of screws 18a. 7

Alternatively, bell-crank lever 9 which carries intermediate wheel 15 may be mounted on a stub shaft whose axis may or may not coincide with the axis of input shaft 8. The axis of this stub shaft, however, must lie in the plane defined by the axis of output shaft 2 and of input shaft 3.

The operation of transmission 1b can best be seen from FIGS. 3 and 4. FIG. 3 shows the device in its normal, unloaded position. At that time, output disc 3 tends to run at its maximum speed. FIG. 4 shows the device in its loaded position. In its loaded position, intermediate wheel is urged against a stop 19 on shaft 14. A line A connects the axes'of output shaft 2 and of input shaft 8 of transmission 1]). The path of travel of path of intermediate'wheel 15 on output disc 3 is represented by a curve D. C represents the plane of intermediate Wheel 15. B is a line tangent to the path of contact D between the intermediate wheel 15 and the output disc 3. When the axis ofshaft 14 is above the line A, as seen in FIG. 4, there is an angle BC between the lines B and C. Intermediate wheel 15 therefore tends to follow spiral path D on output'disc 3 and to travel away from shaft 2 and to travel toward shaft 3 as the transmission 1b is loaded.

. Intermediate wheel 15 is then urged against stop 19 on shaft 14 and the speed of rotation of output disc 3 is at a minimum, the torque then being a maximum. Angle BC is usually not very large, depending on the adjustment of screw 12 which determines the bias of springlil and the torque required to rotate shaft 14 about pivot 8.

Upon the assumption that a load is placed on the output pulley P; disc 3 will tend to slow down and present a higher reaction load to intermediate wheel 15. The

input disc 6 will roll intermediate wheel 15 on output.

shaft-14 will continually seek an equilibrium position so that the output torque and speed match the load. The threshold where the transmission starts to shift away from shaft 2 and toward shaft 8 is determined by a bias spring 10. The type of response can be controlled varying the bias of spring 10; i.e., by having a spring'rate increasing, decreasing, or constant.

What is claimed is:

1. A self-adjusting, variable-speed transmission, including, a frame, an input disc mounted for rotation in said frame, an'output disc mounted for rotation in said frame and having a face partially overlying and substantially parallel to the face of said input disc, an intermediate shaft, means for mounting said intermediate shaft for pivotal movement substantially parallel to the faces of said discs and from one side of a line connecting the centers of said discs to the other side of said line, an intermediate wheel mounted ontsaid intermediate shaft for movement axially and in rotation thereabout and having a surface in contact with the face of said input disc and output disc, a pair of stops on said frame cooperating with a portion of said means for mounting said intermediate shaft to limit the movement of said intermediate shaft, and means of biasing said means for mounting said intermediate shaft into engagement with one of said stops.

2. Aself-adjusting, variable-speed transmission, including, a frame, an input-disc mounted for rotation in said frame, an output disc mounted for rotation in said frame and having a face overlying and substantially parallel with a portion of the face of said input disc, a stub shaft on said frame, a bell crank lever pivotally mounted on said stub shaft, an intermediate shaft mounted on said bell crank lever and movable by said bell crank lever from one side of a line connecting the centers of said'discs to the other side of said line, an intermediate wheel mounted for axial and rotary movement on said intermediate shaft,

a ring forming a part of 'said intermediate wheel and having engagement at its outer surface with a portion of said input disc and with a portion of said output disc, a pair of stops on said frame, a flat spring connected at one portion to said bell crank lever and bearing at another portion against one of said stops, a coil spring biasing said bell crank lever for rotation about said stub shaft in one direction and toward one of said stops, means on said bell crank lever cooperating with the other of said stops for limiting the movement of said bell crank lever in the opposite direction.

3. A self-adjusting, variable speed transmission, including, a frame, an input disc mounted for rotation in said frame, an output disc mounted for rotation in said frame and having a face overlying and substantially parallel with a portion of the face of said input disc, a bell-crank lever pivotally mounted on said frame, an intermediate shaft mounted on said bell-crank lever and movable by said bell-crank lever from one side of a line connecting the centers of said discs to the other side of said line, an intermediate wheel mounted for axial and rotary movement on said intermediate shaft and having a rim engag- 7 ing with the faces of said input disc and of said output disc, and a pair of stops on said frame limiting the rotation of said bell-crank lever in both directions.

4. A self-adjusting, variable speed transmission, including, a frame, an'input disc mounted for rotation in said frame, an output disc mounted for rotation in said frame and having a face overlying and substantially parallel with a portion of the face of said input disc, an intermediate Wheel mounted for axial and rotary movement on said frame and having engagement at its outer surface with a portion of said input and with a portion of said output disc, a pair of stops on said frame, a flat spring connected at one portion to the means mounting said intermediate wheel in said frame and hearing at another portion against one of said stops, a coil spring biasing said means for mounting said intermediate wheel in said frame in one direction and toward one of said stops, and means for mounting said intermediate wheel in said frame for limiting the movement of said means in the opposite direction.

5. A self-adjusting, variable speed transmission, including, a frame, an input disc mounted for rotation in said frame, an output disc mounted for rotation in said frame and having a face overlying and substantially parallel with a portion of the face of said input disc, an intermediate shaft mounted on the frame, an intermediate wheel mounted for axial and rotary movement on the intermediate shaft, 2. ring forming part of said intermediate wheel and having engagement at its outer surface with a portion of said input disc and with a portion of said output disc, and an inertia-actuated means operably connected to the shaft to mount the shaft for pivotal inertial 'movement of its longitudinal axis along a curved path that is substantially parallel to'the faces of the discs and from one side to the other of a line connecting the centers of the discs.

References Cited by the Examiner UN TED STATES PATENTS 1,189,109 6/16 Holden Q 74-190.5 1,216,626 2/17 Tarrisse 74l90.5 2,596,538 5/52 Dicks 74 190.s 2,917,934' 12/59 Nielsen ;74--l90.5

Rouverol 742( 0 DON A. WAITE, Primary Examiner. 

5. A SELF-ADJUSTING, VARIABLE SPEED TRANSMISSION, INCLUDING, A FRAME, AN INPUT DISC MOUNTED FOR ROTATION IN SAID FRAME, AN OUTPUT DISC MOUNTED FOR TOTATION IN SAID FRAME AND HAVING A FACE OVERLYING AND SUBSTANTIALLY PARALLEL WITH A PORTION OF THE FACE OF SAID INPUT DISC, AN INTERMEDIATE SHAFT MOUNTED ON THE FRAME, AN INTERMEDIATE WHEEL MOUNTED FOR AXIAL AND ROTARY MOVEMENT ON THE INTERMEDIATE SHAFT, A RING FORMING PART OF SAID INTERMEDIATE WHEEL AND HAVING ENGAGEMENT AT ITS OUTER SURFACE WITH A PORTION OF SAID INPUT DISC AND WITH A PORTION OF SAID OUTPUT DISC, AND AN INERTIA-ACTUATED MEANS OPERABLY CONNECTED TO THE SHAFT TO MOUNT THE SHAFT FOR PIVOTAL INERTIAL MOVEMENT OF ITS LONGITUDINAL AXIS ALONG A CURVED PATH THAT IS SUBSTANTIALLY PARALLEL TO THE FACES OF THE DISCS AND FROM ONE SIDE TO THE OTHER OF A LNE CONNECTING THE CENTERS OF THE DISCS. 